The molten salt heater or FX is an electric circulation heater mounted with vertical flow orientation. It is designed to provide 75kW of heat to the salt and is sized at nominal +10% at 82kW to hit that target. The supply power for the heater is to be 480V, three phase. The heater has a control board with Watlow controllers that can communicate with the control system.

    As with all the wetted components in the system, the FX is designed for 60% Sodium nitrate and 40% Potassium nitrate molten salt at temperatures up to a maximum of 1085°F (585 °C). It is constructed from 3014L stainless steel and the lid seal is welded rather than sealed with a gasket to avoid leakage. It is designed to have less than a 2psi pressure drop at the required flow of 1.5GPM of molten salt.

    The maximum diameter is the ANSI 12 150# flange and the overall length and height is 60 inches. Process piping is 3/4 NPS weld and the inlet is at the bottom to allow full drainage of the FX and the outlet is perpendicular to the axis of the tank at the top of the heated length. The exterior of the FX shell is wrapped with 6 inches of mineral wool insulation.